Telephone signaling system



' Apr. 3, 1923.

W. A. RHODES TELEPHONE SIGNALING SYSTEM Filed Oct. 25, 1919 2 sheets-sheet 1 IN V EN TOR.

A TTORNEY.

v W. A. RHODES TELEPHONE SIGNALING SYSTEM Filed Oct. 425, 1919 4 2 sheets-Sheet; 2

Y Q INVENTOR.

Patented Apr. 3, 1923.

UNITE WILLIAM A. RHODES, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEPHONE SIGNALING SYSTEM.

Application filed October 25, 1919. Serial No. 333,320.

T all whom. it may concern:

Be it known that I, VILLIAM A. RHODES, residing at New York, in the county of New York and State of New York, have invented certain Improvements in Telephone Signaling Systems, of which the following is a specification.

This invention relates to telephone sys terns, and more particularly to means for 1 providing disconnect and busy signals for such systems.

The invention consists in the provision of improved means whereby a signal is trans mitted to an operator at an originating posi- 1 tion for informing said operator to disconnect her cord from a recording toll trunk. It further consists in the provision of improved means for furnishing busy indications on local connections. Other and further objects of the invention will hereinafter appear.

A telephone callbetween subscribers lines associated with different central offices or eX- changes is completed by means of trunk cir- 2 cuits interconnecting such offices. The operator at the office wherein the call originates communicates with a connecting operator at the exchange with which the called subscribers line is associated, and then connects her cord circuit with a trunk circuit designated by the latter opera'tor which trunk circuit is then connected with the line of the called subscriber and the call is completed. Should the line of the called subscriber be found busy, the operator at the central oflice where the called subscribers line terminates will connect the trunk circuit with one of a set of busy back jacks. These busy back jacks are connected with busy back circuits which include apparatus which operates intermittently and when associated with the trunk circuits and the cord circuits of the connecting and initiating operators cause a supervisory signal at the initiating operators position to flash and inform the operator of the busy condition of the called line. The calling subscriber is also informed in case the called line is busy by a tone produced in the receiver at the substation, and upon receiving such indication should restore the receiver to its hook.

Should the operator, after connecting one end of her cord circuit with the calling line, find that a long distance or toll call is desired, she will connect the other end of said cordwith a trunk circuit terminating at a toll recording operators position. After the calling subscriber has transmitted the desired long distance number to the recording operator, and the latter has disc0nnected, the originating operator should immediately disconnect her cord circuit from the calling line because the recording operator after disconnecting immediately orders up the calling subscribers line over a toll switch-, ing trunk in a well known manner, and, if the originating operator is not prompt in disconnecting, the calling subscribers line will be held busy and a connection will not be built up through a toll switching position without undue delay. Therefore, in order that good trafiic conditions may prevail, it is necessary that the local operator should disconnect her cord circuit as soon as possible. Accordingly it is one of the principal objects of this invention to provide a peremp-' tory signal at the local operators position in order to insure a prompt disconnect on the part of the local operator when the recording operator disconnects.

ing trunk and a recording toll operators position.

In Fig. 1 as illustrated a subscribers station and a type of cord circuit and trunk circuit suitable forcompleting local calls therefrom to another subscribers station. These types of circuits are well known in the art and only portions thereof essential for the operation of this invention are illus-' trated. The subscribers station S terminates in jack J and adapted to be. associated therewith is-a local cord circuit A with the customary plugs P and P Associated with the ring side of cord A are supervisory relays 1 and 2 which respectively control supervisory lamps 3 and 4. The local cord circuit A may be associated with the local trunk circuit B by means of plug and jack J Associated with the talking conductors of trunk B is the supervisory relay 5 which serves when operated to close a short circuit about the high resistance'winding of relay 6 which controls the operation of relay 2 of cord A. The relay 6 controls the usual type of guard or disconnect signal, such as lamp 7 associated with the sleeve relay 8 of the plug P In Fig. 2 is shown the busy back circuit C. If the called line is found busy the operator at the plug end of trunk B associates plug P with jack J 2 of the circuit C, and a busy back signal to the subscriber S and also to the operator at A is thereby provided, as will later appear. Included in the sleeve conductor of circuit C is the relay 9 which is energizedupon the association ot' the plug P and ack J The operation of this relay serves to energize relays 10, ll, 12 and 1.3 intermittently. An interrupter 14 operating continuously, places a tone on the subscriber-s line each time relay 13 is energized and each time relay 11 is released super- Visory lamp 4 of cord A. is flashed.

In Fig. 3 is illustrated a recording trunk D and an operators .position E. When a toll or a long distance connection is desired the operator at A will insert plug P in jack J of recording trunk D, whereupon relay 15 which is associated with the talking conductors of the recording trunk will operate, causing lamp 16 to light. The recording operator E will respond by inserting plug P, in jack J thereby operating relay 17 and extinguishing lamp 16, and after having ascertained the number desired will dissociate plug P from jack J The removal of said plug will cause the release of relay at of recording trunk D as will be pointed out later. The relay 4? upon releasing will con nect lead 19 to ground through a contact of relay 18, which operated when the recorder answered, whereupon the relays l0, ll, 12 and 13 will operate and set in operation re lay 54 which is also grounded by the release of relay 4?. Relay 54 operating intermittently will cause the supervisory lamp 4: associated with cord A to flash rapidly, and thus notify the operator thereat to take down the connection between the subscriber S and recording trunk D in order that said station line shall not test busy, should the toll operator wish to order up and hold the line over a toll switching trunk.

The invention may now be more fully understood from the following description of its operation:

In response to a call from station S, the operator A will insert plug P into ark J and if said operator finds that the sub scriber S desires a local connection with a line associated with another central office, she communicates with the operator at such office by means of a call wire circuit, and is informed by the latter operator of a suitable trunk circuit, such as the trunk circuit B, with which to connect her cord circuit, such as the'cord circuit A. When the cord circuit A is connected with trunk B by means of the plug P being inserted in the jack J the following circuit is completed. From battery, filament of lamp l, resistance 21, sleeve contacts of plug P and jack J, to ground. The closing of this circuit will light lamp l. The insertion of plug P into jack J also closes the following circuit: From one side of battery :22, tip conductor of cord A, tip contacts of plug P and jack 5,, tip conductor of trunk B upper left hand winding of coil 23, conductor 24, low and high resistance windings of relay 6, conductor 25, lower left hand winding of coil 23, ring conductor of trunk B, ring contacts of jack J and plug P ring conductor of cord A, winding of relay 2, to opposite side of battery 22. The upper windings of relay 6, however, is

of sufliciently high resistance so that the closing of this circuit will not at this time operate supervisory relay 2. Relay 6 is operated at this time and lights lamp 7 over the following circuit: From ground, lower winding of relay 8 back contact and armature of said relay, armature and contact of relay 6, conductor 70, filament of lamp 7 to battery. Relay 8 is so adjusted that it will not operate at this time. The local. call is completed by the operator at the central office with which the called subscribers line is associated by inserting the plug 1? of trunk B into the jack of the called subscribers line. When the called subscriber (not shown) responds, the following circuit is closed: From ground, upper right hand winding of: coil 23, tip conductor of cord B, tip contact of plug P out over the sub scribers line in a well understood manner, through the subscribers station back over the subscriber's line, ring contact of plug P winding of relay 5, lower right hand winding of coil 2?, to battery 26. The closing of this circuit will energize relay 5, which will pull up its armature and close a short circuit including conductors 27 and 28 about the high resistance winding of relay 6 so that the circuit formerly closed through relay f3 will no longer include the high resistance winding of relay 6, and relay will. now operate. closing a circuit from grounded battery, filament of lamp 4, low resistance :29. armature and contact of relay 2 to battery. The closing of this circuit will extinguish signal lamp 4, and thus inform the operator at A that the connection has been the plug P oi? trunk B- into one of the jacks a.

of the busy back apparatus shown in Fig. 2.

Such, for example, as the jack J thereby closing the following. circuit: From battery, filament of guard or disconnect lamp 7, winding of relay 8, sleeve conductor of plug P sleeve contacts of plug P and jack J sleeve conductor of jack J and winding of relay 9 to ground. This circuit will operate relay 9 and close the following circuit: From ground, armatureand contact of relay 9, conductor 30, winding of relay 10, conductor 31, back contact and armature of relay 12 to battery 32. This circuit will operate relay 10 and close a circuit from battery 33, contact and armature of relay 10, conductor 34, winding of relay 11 to ground, thereby causing the last mentioned relay to operate. The operation of relay 10 also closes a circuit from battery 33, contact and armature of relay 10, conductor 35, lower winding of relay 13 to ground, thus operating the latter relay. An additional circuit is also closed by the energization of relay 10, from battery 33, contact and armature of relay 10, conductors 3 1 and 36, winding of relay 12 to ground. ielay 12 which is slower in action than relays 11 and 13is after an interval operated by this circuit and pulls up its armature and breaks the circuit through relay 10. Relay 10 is slow in releasingand an interval elapses before its release occurs, during which a circuit is closed from battery 32 through the armature and contact of relay 12, conductor 37, upper winding of relay 13 to ground and current flowing in both windings of relay 13 causes it to release, since the windings of relay 13 are connected differentially. Relay 10, upon releasing releases relay 11 and by opening the circuit through the lower winding of relay 13, causes it to operate. More over, the release ofrelay 10 results, after an interval, in the release of relay 12, which in turn causes the release of relay 13 and the restoration of the entire circuit to the condition it was in when relay 9 operated. The cycle of operation described above, consequently will be repeated until such time as relay 9 is released. During this cycle relay 13 will operate upon the energization of either of the relays 10 and 12 and will release upon the energization or upon the deenergizat-ion or both, and will therefore operate and release at twice the frequency of relay 11. Each time relay 11 operates a circuit will be closed from ground,

upperwinding of relay 17 to ground.

ate and release .relay 2 by a-circuit over the tip and ring conductors of cord A including battery 22, and the supervisory lamp 4 of said cord will be flashed as previously out lined. A tone is also induced in the transformer coil 38 due to the operation of the buzzer 14 and this tone when relay 13 is operated, is transmitted to the calling sub-- scriber over the tip conductor of the circuit B "and'tip and ring conductors of circuit .A and of the subscribers line. This tone is interrupted intermittently at the frequency of operation of relay 13 and will furnish a distinctive signal to the subscriber. subscriber upon receiving this tone in the receiver willresto-re it to its hook, and the operator at A noting the flashing of her supervisory lamp will take down the connections at A. The relay 6 of trunk B will then release and the shunt around lamp 7 will be romoved and the lamp lighted. This The serves as a disconnect signal to the operator at B, who disconnects plug P from jack J and consequently restores circuit C to normal.

Should the operator at A, in responseto a call from station S, find that a long distance or toll call is desired, she will insert plug P injack J 3 of the recording trunk D, which terminates at a recording toll operators position E, thereby establishing the following circuit: From battery, supervisory lamp 4, resistance 21, sleeve conductor of I cord A, sleeve contacts of P and jack J sleeve conductor of circuit D, upper winding of relay 41, conductor 42, contact of relay 18 to ground. Relay 41 will be energized by the previously described circuit, but in operating will perform no useful function at this time. The insertion of plug P in jack J also closes. a circuit'from battery 22, tip and ring conductors of cord A, including winding of relay 2, tip and ring contacts of plug P and jack J tip and ring conductors of trunk D, winding of relay 51, conductors 48 and 49 and winding of high resistance relay 15. 51 due to the high resistance of relay 15 receive insufficient current at this time to permit their operation, but relay 15 will be energized by this circuit, and upon operating closes v the. following circuit: From battery, front contact andarmature of said relay, conductor 50, armature and back contact of relay 17, fila1nent of lamp16 to ground, thereby lighting lamp 16. The recording operatorE, observing that the lamp 16 is lighted, willinsert plug P in jack J 2 and establish the following circuit: From battery, sleeve contacts of plug 1? and ackJ This circuit energizes relay 17, which in operating extinguishes *lamp 16 and -closes a locking circuit from. ground through lower.

and contact of relay 15 to battery. The insertion of plug P in jack J also establishes a circuit through the winding of the low resistance relay 60 in the operators cord E, over the tip. and ring contacts of plug P and ack J and winding of high resistance relay 15 of the trunk D, thus connecting the low resistance relay 60 and high resistance relay 15 in parallel, thereby reducing the resistance in the circuit sufficiently to allow relays 2 and 51 to operate. The operation of relay 2 extinguishes the supervisory lamp 4 in an obvious manner, The operation of relay 51 closes a circuit over its armature and contact from ground, conductor 52 and winding of relay 47 to battery, said circuit energizing relay 47. The operation of relay 47 removes ground from conductor 46 and thence from conductor 45 and thereby allows relay 18 to operate over a circuit from battery 43, resistance 44, conductor 45, winding of relay 18 to ground. Relay 47 also places ground on conductor 42 so that the subsequent operation of relay 18 does not at this time affect the condition of the A cord sleeve circuit.

V7 hen the recording operator at E- has ascertained the number desired from the operator at A, she removes plug P from jack J,. The removal of said plug disconnects the low resistance therein so that there is in sufiicient current to maintain relays 2 and 51 energized, and they release. The release of relay 51 breaks the circuit previously described for energizing relay 47, and the latter relay upon releasing closes a circuit from ground through its contact and armature, conductor 46, through lower contact and armature of relay 18, conductor 19. through winding of relay 10. back contact and armature of relay 12 to battery 32. The closing of this circuit sets in operation relays 10, 11, 12 and 13, and the apparatus and circuit at C function in a manner similar to that described in connection with the association of trunks B with circuit C. The operation of relay 13 in this case supplies intermittent battery through itslower armature and contact over conductor 20, through the winding of relay 54, conductor 55. lower inner armature of relay 18, conductor 46. normal contact of relay 47 to ground. Relay 54 is energized by this circuit and operates and releases in unison with relay 13. The supervisory lamp 4 of cord A does not light until relay 54 is operated due to the high resistance of the circuit from battery. filament of said lamp, resist ance 21 sleeve contacts of plug P, and jack J through upper low resistance and lower high resistance windings of relay 41 to ground. The operation of relay 54, however, short circuits the lower high re sistance winding of relay 41 and connects ground by way of its armature and contact to the upper low resistance winding of relay 41, thereby permitting suflicient current to flow over the sleeve circuit to light the supervisory lamp 4. Thus each time relay 54 operates, under control of relay 13 in the circuit C, the lamp 4 of cord A will flash, the cycle of operation in circuits C and D, continuing until the operator at A observing the rapid flashing of said lamp, will disconnect plug P from jack J While the invention has been disclosed as embodied in certain specific arrangements which have been deemed desirable, it will be understood that it is capable of embodiment,

in many and widely varied forms without departing from the spirit of the invention as defined in the appended claims.

Having thus described the invention, what it is desired to secure by Letters Patent is:

1. In a telephone system, a trunk circuit, a recording circuit, a cord circuit adapted to be associated with either of saidcircuits, an indicating circuit adapted tobe associated with said trunk circuit or said recording circuit, a difierential relay in said indicating circuit, and a plurality of sequentially operated relays in said indicating circuit for intermittently energizing said differential relay whereby a busy indication is produced in the cord circuit upon the association of the trunk circuit with said indicating circuit and whereby a peremptory disconnect signal is produced in said cord circuit upon the association of said recording circuit with said indicating circuit.

2. Ina telephone system, a trunk circuit, a recording circuit, a cord circuit adapted to be associated with either of said circuits, an indicating circuit adapted to be associated with said trunk circuit or recording circuit, a difierential relay in said indicating circuit, and a plurality of sequentially operated relays in said indicating circuit for intermit tently energizing said differential relay whereby a signal is produced in the cord circuit upon the association of the trunk circuit with the indicating circuit and whereby said signal is produced at double the frequency in said cord circuit upon the association of said recording circuit with said indicating circuit.

3. In a telephone system, a trunk circuit, a recording circuit, a cord circuit associated with the incoming end of said recording circuit, a second cord circuit adapted to be associated with the trunk circuit or with outgoing end or' said recording circuit, an indicating circuit including relays adapted to be associated with said trunk circuit or said recording circuit, means included in said indicating circuit whereby a signal is produced in the second mentioned cord circuit upon the association of the cord circuit with said trunk circuit and said trunk circuit with the indicating circuit, and means whereby the association of said second cord circuit directly with said recording trunk causes said indicating circuit, to operate a signal in the second mentioned cord at twice the frequency of the first mentioned signal, said means being controlled by the dissociation of the first mentioned cord circuit from the incoming end of said recording circuit.

4. In a telephone system, a subscribers station, a cord circuit adapted to be associated therewith, a busy back circuit, a trunk circuit whereby said cord circuit is connected with said busy back circuit, a relay in said busy back circuit controlled by the connection of said trunk with said busy back circuit, a plurality of relays controlled by said relay, a differential relay controlled by said plurality of relays whereby an intermittent signal is produced in the cord circuit, an interrupter, and a transformer controlled by said differential relay and said interrupter whereby a tone is produced at said subscribers station upon the connection of said trunk with said cord circuit and busy back circuit.

5". In a telephone system, a cord circuit, an indicating circuit, a recording circuit, a second cord circuit associated with said recording circuit in talking connection With said first cord circuit, means in said recording circuit responsive to the disconnection of said second cord circuit therefrom for connecting said indicating circuit with said recording circuit, a plurality of sequentially operated relays in said indicating circuit responsive to'the connection of said recording circiut therewith, a first relay in,

said indicating circuit controlled by said sequentially operated relays, and a second relay in the recording circuit operable in uni son with said first relay for operating'a sig nal in the first mentioned cord circuit.

In testimony whereof, I have signed my name to this specification this 23rd day of October, 1919.

l/VILLIAM A. RHODES. 

